The invention relates to a method of manufacturing a semiconductor device, which method starts with a semiconductor wafer which at a first side is provided with a top layer of semiconductor material situated on an insulating layer, after which semiconductor elements and conductor tracks are formed on this first side of the semiconductor wafer, the semiconductor wafer is glued with this first side to a support wafer, and material is removed from the semiconductor wafer from the other, second side until the insulating layer has been exposed.
The support wafer with the layer comprising semiconductor elements glued thereto may subsequently be subdivided into individual semiconductor devices in usual manner, which devices may comprise one or several semiconductor elements such as bipolar or field effect transistors.
The semiconductor elements in semiconductor devices thus manufactured are formed in the comparatively thin top layer of semiconductor material which is in an insulated position. Detrimental capacitances are absent, so that these devices can process signals of very high frequencies.
EP-A-570 224 discloses a method of the kind mentioned in the opening paragraph wherein the basic semiconductor wafer is a silicon wafer whose top layer situated at the first side consists of monocrystalline silicon, while the insulating layer is made of silicon oxide. This semiconductor wafer is formed by wafer bonding. In this process, two wafers of silicon are first provided with a layer of thermal oxide at one side. Then these wafers are bonded together with their oxidized surfaces under pressure and at a high temperature. Finally, one of the wafers thus bonded is subjected to a polishing and etching treatment whereby so much silicon is removed that the desired semiconductor wafer is formed.
The insulating silicon oxide layer serves as a layer at which the material-removing treatment from the second side of the semiconductor wafer stops automatically when the method mentioned in the opening paragraph is being carried out. The insulating layer, which itself is not removed during this, may then be used as an insulation for the semiconductor elements. Windows may be provided in this layer for external contacting of the semiconductor device. To protect the semiconductor device thus formed against mechanical and chemical damage which may arise during further mounting or enveloping, a usual passivating layer of a scratch-proof material, which is practically impermeable to moisture, to alkali atoms such as sodium, and to other mobile metallic impurities, should be provided on the silicon oxide layer.
While such a passivating layer is being provided, the semiconductor wafer must be heated to a temperature of between 300 and 400.degree. C. in practice. After the semiconductor wafer has been glued to the support wafer, however, a treatment at a temperature higher than 200.degree. C. may damage the glue connection. The provision of the passivating layer referred to above accordingly forms a problem.